Golf club

ABSTRACT

A golf club which comprises a head which is less deformable by the heat in welding. Separate reinforcing members  12  and  13  are provided on inner surface of a front edge  8 A of a crown shell  8.  Thus, the front edge  8 A side is thickened and then the upper edge  4 A of the face shell  4  is joined to the front edge  8 A of the crown shell  8,  by welding. The front edge  8 A of the crown shell  8  is formed with a plurality of projections  11  which are anchored by the upper edge  4 A of the face shell  4.  front edge  8 A of the crown shell  8  is thickened by adding the thickness of the reinforcing members  12, 13  to the thickness of crown shell  8  itself. Thus, thermal deformation and the sinking of the front edge  8 A at the time of welding can be prevented, thus enabling the upper edge  4 A to be joined to the front edge  8 A as designed.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a golf club with a head made ofa plurality of separate shells, having a shaft connected thereto.

[0003] 2. Description of the Prior Art

[0004] Conventionally, in order to produce wood golf club heads orso-called “metal Wood”, it is known art to join a plurality of metallicshells together. In those types of heads, respective peripheries ofplural metallic shells are integrally welded to one another.

[0005] As golf club heads are progressively large-sized, with lowercenters of gravity thereof being pursued, respective separate shells forconstructing a head also are getting thinner and thinner. For example,in the case that a beta titanium alloy is used, face is normally as thinas 2.5 to 3.0 mm, sole and crown are each as thin as 1 mm or below. Whenwelding such thin separate shell together, there occurs a problem thatheat by the welding causes deformation. More specifically, when weldinga crown to a face, a front edge of the crown is likely to sink towardthe inside. In that case, excessive grinding would be needed as apost-processing to obtain a predetermined configuration, so that theresultant thickness of welded portions becomes too small. As a result, agolf club head thus produced is likely to become irresistible to impactat the time of striking balls, resulting to a likelihood to cause crackstherein.

[0006] On the other hand, while the peripheral edges of a plurality ofmetallic shells are welded together in metal wood golf clubs, welding isperformed by abutting the adjacent peripheral edges to one another, sothat there is another problem that an excessive amount of welding beadenters inside. While welding bead is to be heaped up in an approximatelyeven manner along the welding advancing direction, if a portion of thewelding bead sinks into the inside, then the portion is depressed, andthus another welding bead must be heaped up again. If beads arerepeatedly heaped up this way, more welding heat is applied due to thewelding, so that the undesirable deformation is more likely to occur. Onthe other hand, if the excessive welding bead is heaped, then it wouldbe difficult to visually confirm the configuration of parts whererespective shells are joined. Further, there would occur a furtherproblem that the applied heat causes a change in strength property oftitanium alloy material so that the fragility is increased, thus leadingto the possible destruction of the neighborhood of the parts tobewelded. Even though non-solution treatment material is used, yet thewelding bead is likely to cause deformation to some extent.

[0007] Whereas, in paragraphs 0008 to 00010 in Japanese Un-Examinedpatent publication No 11-114106 is disclosed a method for manufacturinga golf club, wherein in a golf club head comprising a hollow metallicbody shell and a face shell joined to an opening of said body shellwhich is open to the face shell, at least one of an end face of theopening of the body shell or an edge of the face shell is formed with aplurality of projections to be abutted to the other, while beads 15 areburied in recesses formed between the projections, to fix the face shellto the opening of the body shell; and also a method for manufacturing agolf club wherein a welding member is heated while being abutted to therecesses formed between the above projections when abutting the faceshell to the head body, so that the welding member is fused to be filledin said recesses, to thereby fix the face shell to the opening of thehead body. The prior art teaches that such methods ensure beads to beproperly positioned in the recesses between the projections in aposition where the body shell and the face shell are joined, withoutoverlapping with the body shell or the face shell, so that the faceshell is lightened.

[0008] According to the prior art, however, there still remains aproblem that when joining respective thin separate shells together bywelding, they are deformed due to the heat in welding. Further, theprior art involves a further problem that as one of the members to beabutted is provided with projections, and beads are buried in recessesformed between the projections, excessive amount of welding beads islikely to enter the inside through the recesses.

SUMMARY OF THE INVENTION

[0009] To eliminate the above problems, it is, therefore, a main objectof the present invention to provide a golf club having a headconstructed by joining a plurality of metallic shells, and a shaftconnected to the head, wherein said head is less likely to be deformedby the heat in welding.

[0010] It is another object of the present invention to provide a golfclub having a head constructed by joining a plurality of metallicshells, wherein said head is protected from the excessive welding beadsentering the inside and excessive heat being applied thereto.

[0011] To attain the above objects, there is provided, in accordancewith a first aspect of the invention, a golf club, which comprises: ahead formed by joining a plurality of separate shells one another, saidseparate shells including a first separate shell and a second separateshell; a shaft connected to said head, and a reinforcing means providedfor reinforcing joint strength between said first separate shell andsecond separate shell, said reinforcing means being provided in aperipheral portion of at least said first separate shell.

[0012] With the structure thus made, the reinforcing means can improvethe joint strength between the first and second separate shells to bejoined. Thus, thermal deformation at the time of welding can beprevented.

[0013] According to a second aspect of the invention, there is provideda golf club according to the first aspect, wherein the peripheralportion of said first separate shell is thickened partially or entirely.

[0014] According to a third aspect of the invention, there is provided agolf club according to claim 1, wherein said reinforcing means is aseparate reinforcing member which is partially or entirely provided onan inner surface of said peripheral portion of said first separateshell, so that it is thickened.

[0015] With the structures, welding portions in the shells to be joinedare reinforced and thickened, thereby enabling the shells to withstandthe heat in welding, and thus they are prevented from being thermallydeformed by the heat. Further, said head is protected from the excessivewelding beads entering the inside and excessive heat being appliedthereto.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Other objects, features and advantages of the invention will beapparent to those skilled in the art from the following description ofthe preferred embodiments of the invention, wherein reference is made tothe accompanying drawings, of which:

[0017]FIG. 1 is an exploded perspective view showing a golf clubaccording to a first embodiment of the invention.

[0018]FIG. 2a is a section of a golf club according to the firstembodiment of the invention, while FIG. 2b is an enlarged sectionthereof.

[0019]FIG. 3 is a bottom view of a crown shell of a golf club accordingto the first embodiment of the invention.

[0020]FIG. 4 is an exploded perspective view showing a golf clubaccording to a second embodiment of the invention.

[0021]FIG. 5 is a bottom view of a crown shell of a golf club accordingto the second embodiment of the invention.

[0022]FIG. 6a is a section of a golf club according to a thirdembodiment of the invention, while FIG. 6b is an enlarged sectionthereof.

[0023]FIG. 7 is an exploded perspective view showing a golf clubaccording to the third embodiment of the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0024] Hereinafter will be described an embodiment of the invention withreference to the attached drawings.

[0025] In FIGS. 1 to 3 showing a first embodiment of the invention, ametallic wood golf club commonly known as “metal wood club”, comprises ahead 1 having a hosel 2 serving as a shaft attachment portion and ashaft 3 connected to the hosel 2. The head 1 is integrally formed byjoining a plurality of metallic shells together. In the presentembodiment, such metallic shells consist of: a face shell 4 on a front;a sole and side-peripheral shell 7 forming a sole 5 and a peripheralside portion 6; and a crown shell 8, which are made of beta typetitanium alloy, respectively, and joined together by welding therespective peripheral edges one another. In the meantime, the head 1 hasa hollow portion 9 with a shaft attachment pipe 10 disposed thereinthrough the hosel 2, while a lower portion of the shaft 3 is insertedinto said pipe 10. The thickness of the crown shell 8 is smaller thanthat of the sole and peripheral side shell 7, while the thickness of thesole and peripheral side shell 7 is smaller than that of the face shell4.

[0026] The crown shell 8 has a front edge 8A which is formed with aplurality of projections 11, while the face shell 4 has an upper edge 4Aso that said projections 11 may be anchored by resting on the upper edge4A. Each projection 11 has a projection length A of about 2 to 3 mm,which is at most equal to a thickness B of the upper edge 4A of the faceshell 4, or otherwise, slightly shorter than the thickness B. While eachprojection 11 has a width C of about 2 mm for example, which is nearlyas wide as the said projection length A. In the embodiment, there arefour projections 11 laterally spaced from each other.

[0027] Further, the front edge 8A of the crown shell 8 has reinforcingmembers 12 and 13 integrally fixed thereto along the inside of the frontedge 8A. These reinforcing members 12 and 13 are provided at right andleft sides of the front edge 8A, along the front edge 8A only, eachbeing formed into a thin plate, having a thickness D of about 1 mm forexample, approximately equal to a thickness E of the said front edge 8A,while a width W of about 5 mm so that each extends along the front edge8A. In the embodiment, these reinforcing members 12 and 13 areintegrally provided at both sides of the front edge 8A, by spot weldingor the like. These reinforcing members 12 and 13 have respective frontedges 12A and 13A, which project out from the end of the front edge 8Aby a projection length F that is about 1 mm, for example, less than theaforesaid projection length A.

[0028] Next, a manufacture method of a golf club according to theinvention will be described. The head 1 is integrally constructed bywelding the respective edges of the face shell 4, the sole andperipheral side shell 7 and the crown shell 8 one another. While thewelding is performed by TIG welding, the sole and peripheral side shell7 and the crown shell 8 have such small thickness E as thin as about 1mm or less, as above-mentioned, and thus a value of an electric currentfor the welding should desirably be set at 40 to 50 A that is lower than80 to 90 A for the welding of the face shell 4 having the largerthickness B of 2 to 3 mm or above.

[0029] When welding the upper edge 4A of the face shell 4 to the frontedge 8A of the crown shell 8, the distal ends of the reinforcing members12 and 13 are abutted to the rear face of the face shell 4 while theprojections 11 are allowed to rest on the upper edge 4A of the faceshell 4, thereby locking the former shell relative to the latter shell.By arranging the face shell 4 and the crown shell 8 this way, aclearance 14 of about 1 mm, for example, is formed between the rear faceof the face shell 4 and the front edge 8A of the crown shell 8 in thesereinforcing members 12 and 13. Then, welding is performed in such amanner that beads 15 are placed between the upper edge 4A of the faceshell 4 and the front edge 8A of the crown shell 8. At this moment, eventhough the front edge 8A of the crown shell 8 is subjected to thewelding heat so that it is exposed to the risk of thermal deformation,yet the front edge 8A is reinforced by the reinforcing members 12 and13, so that it can withstand such thermal deformation and prevent thedeformation. Further, as welding is performed with the projections 11being anchored in such a manner that rests on the upper edge 4A of theface shell 4, the front edge 8A can be prevented from sinking into theinside of the head 1 by the thermal deformation, whereby the upper edge4A of the face shell 4 can be welded to the front edge 8A of the crownshell 8 as originally designed. Additionally, as the front edges 12A,13A of the reinforcing members 12, 13 protruding from the front edge 8Aof the crown shell 8 are abutted to the rear surface of the face shell 4to thereby form the narrow clearance 14 between the laterally pairedreinforcing members 12 and 13, the reduced amount of the sinking beads15 as well as the better formation of the beads 15 can be achieved.

[0030] As is apparent from the foregoing, according to the foregoingembodiment of the invention, there is provided a golf club comprisingthe head 1 and the shaft 3 connected thereto, said head 1 consisting ofthe face shell 4; the sole and side-peripheral shell 7 forming the sole5 and the peripheral side portion 6; and the crown shell 8, wherein thereinforcing members 12 and 13 are provided partly along the front edge8A of the crown shell 8 so as to thicken the front edge 8A side of thecrown shell 8 by adding the thickness D of the reinforcing members 12and 13 to its thickness E, and then welding is performed, wherebythermal deformation at the time of welding can be prevented.

[0031] Whereas, in order to enlarge a sweet area, the center of gravity(hereinafter called C.G., not shown in the drawings) of the head 1 mustbe lowered and the depth of the C.G., defined as a distance between theC.G. of the head and the face shell 4, must be prolonged, and thus thecrown shell 8 must be formed thin. According to the embodiment of theinvention, however, only the front edge 8A of the crown shell 8 isformed thick, so that the thermal deformation at the time of welding canbe prevented, even though the crown shell 8 is formed thin as a whole.

[0032] Further, the front edge 8A of the crown shell 8 is provided on apart of its inner surface with the separate reinforcing members 12, 13so that the front edge 4A of the face shell 4 and the front edge 8A ofthe crown shell 8 can be welded to each other with the crown shell 8being comparatively thickened at the front edge 8A side, whereby thefront edge 8A of the crown shell 8 can have an increased thickness byadding the thickness D of the reinforcing members 12, 13 to itsthickness E, thereby preventing the thermal deformation at the time ofwelding. Specifically, as the separate reinforcing members 12, 13 arefixed to the inner surface of the front edge 8A of the crown shell 8,scrap pieces produced when forming the respective shells 4, 7 and 8 canbe used therefor, while if these reinforcing members 12 and 13 areformed thin in advance, to the preset small thickness D, the front edge8A of the crown shell 8 can be formed to the preset thickness of “E+D”.Furthermore, as the reinforcing members 12 and 13 are separate from thecrown shell 8, they can be easily arranged in any position on the crownshell 8 you like, while as the reinforcing members 12 and 13 are onlyarranged along the front edge 8A of the crown shell 8, they can bereduced to a minimized size to be lightened, thus minimizing theinfluence on the weight distribution of the head 1.

[0033] Additionally, the front edges 12A and 13A of the said reinforcingmembers 12 and 13 are allowed to protrude from the front edge 8A of thecrown shell 8 with the front edge 8A side being thickened (E+D), andthat the upper edge 4A of the face shell 4 and the front edge 8A of thecrown shell 8 are joined to each other by welding, with the distal endsof the front edges 12A and 13A being abutted to the rear surface of theface shell 4, whereby there can be formed the narrow clearance 14 of apreset small dimension, between the rear surface of the face shell 4 andthe front edge 8A of the crown shell 8, thus enabling better beads 15 tobe formed.

[0034] In addition to the foregoing, as the welding of the upper edge 4Aof the face shell 4 to the front edge 8A of the crown shell 8 isperformed with the plural projections 11 provided on the front edge 8Aof the crown shell 8 being anchored by the upper edge 4A of the faceshell 4, the front edge 8A can be prevented from sinking at the time ofwelding, so that it is possible to weld the upper edge 4A to the frontedge 8A as originally designed.

[0035] In FIGS. 4 and 5 showing a second embodiment of the invention,and in FIGS. 6 and 7 showing a third embodiment of the invention, thesame portions as those described in the foregoing embodiment will bedesignated by the same reference numerals, and their repeated detaileddescriptions will be omitted.

[0036] In the second embodiment, a reinforcing member 21 is integrallyfixed to the inside of the front edge 8A of the crown shell 8 along theedge thereof. This reinforcing member 21 is disposed along an entiretyof the front edge 8A, i.e., continuously from one side of the front edge8A to the other side thereof, having a thickness of about 1 mm, forexample, which is nearly as thin as the front edge 8A, and a width ofabout 5 mm. In the present embodiment, the reinforcing member 21 isintegrally provided by spot welding at both sides of the front edge 8A,having a front edge 21A protruding from the front edge 8A. Theprojection length of the reinforcing member 21 is about 1 mm, forexample, which is smaller than that of the projection 11.

[0037] Accordingly, when welding the upper edge 4A of the face shell 4to the front edge 8A of the crown shell 8, the distal end of thereinforcing member 21 is abutted to the rear face of the face shell 4while the projections 11 are allowed to rest on the upper edge 4A of theface shell 4, thereby anchoring the former to the latter. After that,beads 15 are placed between the upper edge 4A of the face shell 4 andthe front edge 8A of the crown shell 8, to thereby perform the welding.As discussed above, even though the front edge 8A of the crown shell 8is subjected to the welding heat so that it is exposed to the risk ofthermal deformation, yet the front edge 8A is reinforced by thereinforcing member 21, so that it can withstand such thermal deformationand prevent the deformation. Further, as welding is performed with theprojections 11 resting on the upper edge 4A of the face shell 4, thefront edge 8A can be prevented from sinking into the inside of the head1, when welding the upper edge 4A of the face shell 4 to the front edge8A of the crown shell 8.

[0038] As is apparent from the foregoing, the second embodiment also isadvantageous in that thermal deformation at the time of welding can beprevented like the first embodiment, and specifically advantageous inthat as the reinforcing member 21 is provided along the entire length ofthe front edge 8A, it can be reinforced in an entire region of the frontedge 8A.

[0039] In the third embodiment, cladding 31 is integrally provided inadvance on the inside face of the front edge 8A of the crown shell 8,said cladding 31 being provided along the edge 8A only. The cladding 31is provided by putting weld bead, along a part or entire length of thefront edge 8A, having a thickness of about 1 mm, for example, nearly asthin as the front edge 8A, and a width of about 5 mm.

[0040] Accordingly, when welding the upper edge 4A of the face shell 4to the front edge 8A of the crown shell 8, the upper edge 4A of the face4 is abutted to the front edge 8A of the crown shell 8, and then,welding is carried out with the beads 15 being placed between the upperedge 4A and the front edge 8A. Thus, the front edge 8A can be reinforcedby the cladding 31 when the front edge 8A side is exposed to the risk ofthermal deformation by the welding heat.

[0041] Specifically, in a golf club comprising the head 1 having theshaft 3 connected thereto, said head 1 being integrally formed byjoining the face shell 4; the sole and side-peripheral shell 7; and thecrown shell 8, the front edge 8A of the crown shell 8 is partly orentirely provided with the cladding 31, so that the front edge 8A sideof the crown shell 8 is formed thicker by adding the thickness of thecladding 31 to the thickness of the front edge 8A, whereby the thermaldeformation can be prevented like in the first embodiment.

[0042] Also, as the cladding 31 is disposed along only the front edge 8Aof the crown shell B, the cladding 31 can be reduced to a minimum involume, and lightened, without uselessly disposing it where it actuallyis not necessary, thus minimizing the influence on the weightdistribution of the head 1.

[0043] Still also, as the cladding 31 by welding is provided so as tothicken the front edge 8A side of the crown shell 8, it suffices to addthe cladding step to the welding process as a preliminary treatmentprior to welding the face shell 4 to the crown shell 8, said claddingstep being simply providing the cladding 31 in a desired position alongthe front edge 8A of the crown shell 8.

[0044] Incidentally, the present invention should not be limited to theforegoing embodiments, but may be modified within the scope of theinvention. For example, the present invention may apply to the weldingbetween other shells than the face shell and the crown shell.

What is claimed:
 1. A golf club comprising: a head formed by joining aplurality of separate shells one another, said separate shells includinga first separate shell and a second separate shell; a shaft connected tosaid head; and a reinforcing means provided for reinforcing jointstrength between said first separate shell and second separate shell,said reinforcing means being provided in a peripheral portion of atleast said first separate shell.
 2. A golf club according to claim 1,wherein said peripheral portion of said first separate shell isthickened partially or entirely.
 3. A golf club according to claim 1,wherein said reinforcing means is a separate reinforcing member which ispartially or entirely provided on an inner surface of said peripheralportion of said first separate shell, so that it is thickened.
 4. A golfclub according to claim 3, wherein said seperate reinforcing memberprotrudes from an end of said first separate shell.
 5. A golf clubaccording to claim 1, wherein a plurality of projections are provided onan end of at least said first separate shell so that said projectionsare anchored by an end of said second separate shell.
 6. A golf clubaccording to claim 1, wherein cladding is partially or entirely providedon an inner surface of said first separate shell.
 7. A golf clubaccording to claim 1, wherein said head is of a wood type.
 8. A golfclub according to claim 5, wherein said projections protrude by a lengthwhich is less than or at most equal to a thickness of said secondseparate shell.
 9. A golf club according to claim 7, wherein a clearanceis formed between an upper edge of a face shell and a front edge of acrown shell, while a weld bead is provided in the clearance.